ABSTRACT
Background and Aim: The light transmittance through amniotic membrane [AM] has a major effect on the visual acuity after transplantation of this biomaterial for reconstruction of the cornea. In this study, we evaluated role of placental region of extracted AM and histological layers of the amnion on the light transmission ability [transparency]
Material and Method: The AMs were obtained from disk and peripheral [2 cm away from disk edge] regions of the placenta. The light transmission rates of the prepared intact tissues and also of the tissues after removal of the epithelial and spongy layers were measured. We determined the thicknesses of AMs by evaluating the photos of histological sections using software analyses
Results: Peripheral region of the AM was more transparent than the disk region. Histological studies revealed structural differences between epithelial cells of disk and peripheral regions. Removal of the epithelial cells increased the transparency of AMs and omitted the transparency difference between disk and peripheral regions, while, the thickness of the AMs samples of the two regions had significant differences after removal of the epithelial layer
Conclusion: The epithelial cells of the AM, which have stem cell characteristics, play a major role in the light transmission ability of the AM, and thickness of the membrane had no significant impact on its light transmission rate
ABSTRACT
Introduction and Objective: The amniotic membrane [AM] has distinctive characteristics and potentials that make it a proper biomaterial for tissue engineering. There are varieties of methods for preserving the AM. In this study, the AM was preserved using different methods. The effect of preservation on tissue composition and physical and mechanical properties was compared between preserved and fresh samples of the AM
Materials and Methods: The human AM was preserved after being detached from the placenta. It was preserved using either cryopreservation methods [in temperature of -80 ?C, for 6 months] or lyophilization. The preserved AM was histologically assessed using light and electronic microscopy. Mechanical tolerance of the preserved AM was also measured using uniaxial tension test, suture retention test and thickness calculation
Results: This study showed that the value of Fmax and elongation at break in the cryopreserved and lyophilaized AM was smaller than the same value in the fresh AM samples. All of the samples had same tolerance in suture retention test, although lyophilaized samples of the AM were thinner than other types of the samples. Tissue composition [histological properties] regarding epithelial cells and tissue layers of the AM were not the same in different samples
Conclusion: Cryopreservation and lyophilization as two preservation methods of the AM, can affect the tissue composition and physical and mechanical features of the AM. Thus the preservation method for the AM can be chosen regarding the final usage of the AM as a biomaterial